1. Technical Field
The present disclosure relates to a resistive nonvolatile storage device of which resistance value is changed with application of an electric pulse, and to a manufacturing method for the resistive nonvolatile storage device. The present disclosure further relates to a resistive nonvolatile storage apparatus using the plurality of resistive nonvolatile storage devices.
2. Description of the Related Art
Recently, functions of electronic equipment, such as portable information devices and intelligent home appliances, have become increasingly sophisticated with development of the digital technology. Corresponding to the sophistication in functions of the electronic equipment, miniaturization and speedup of semiconductor elements used in the electronic equipment have also been progressed at a high pace. Such a trend has quickly expanded applications of large-capacity nonvolatile memories represented by a flash memory. Furthermore, research and development of a ReRAM (Resistive Random Access Memory) using a resistive nonvolatile storage device has been progressed as a novel nonvolatile memory that is to be replaced with the flash memory. Here, the term “resistive nonvolatile storage device” implies an element having properties to reversibly change its resistance value in accordance with an electric signal, and being able to non-volatilely store information corresponding to the resistance value.
In the above-mentioned resistive random access memory, a resistance change layer of which resistance value is changed is used as a storage element. By applying an electric pulse (e.g., a voltage pulse) to the resistance change layer, the resistance value of the resistance change layer is changed from a high resistance state to a low resistance state, or from a low resistance state to a high resistance state. On that occasion, by storing data such that the low resistance state corresponds to “1” and the high resistance state corresponds to “0”, resistive random access memory can be operated to function as a binary memory. In such a case, it is desirable to distinctively discriminate binary values corresponding to the low resistance state and the high resistance state, to stably cause change between the low resistance state and the high resistance state at a high speed, and to hold the binary values in a nonvolatile fashion.
As one example of the above-described resistive nonvolatile storage device, there is proposed a resistive nonvolatile storage device using a resistance change layer that is in the multilayer form of transition metal oxides having different oxygen contents. For example, International Publication No. 2008/149484 discloses a technique that stabilizes a resistance change phenomenon by selectively generating an oxidation reaction and a reduction reaction at an interface between a transition metal oxide layer having a high oxygen content and an electrode disposed in contact with the transition metal oxide layer.